A fifth generation (5G) mobile communications system makes mobile data traffic increases, the Massive Internet of Things, diversified new services and application scenarios possible in the future. In addition to serving as a unified connection frame, basic 5G new radio (NR) of a new generation cellular network hopefully further increases a data speed, a capacity, a delay, reliability, efficiency, and a coverage capability of the network to a brand new level, and fully utilizes an available spectrum resource of each bit. The 5G designed based on orthogonal frequency division multiplexing (OFDM) new radio will become a global standard, support diversified deployment of 5G devices, and cover diversified spectrums (including coverage of low frequency bands and high frequency bands), and will further support diversified services and terminals.
Although high-frequency transmission provides more bandwidth, the high-frequency transmission has distinctive problems, for example, severe signal fading and a poor penetration capability. Currently, a transmission solution featuring massive multiple-input multiple-output (MIMO) beamforming is considered to enhance coverage of it and overcome the problem of severe fading. Solutions such as space frequency block coding (SFBC), semi-open-loop, and beam-cycling are used for overcoming a problem of a reduced penetration capability caused by blocking. In the foregoing solutions, beams may be beams in different directions, or a beam formed by beams in different directions.
Blocking is often unexpected, and a means of semi-static adjustment of a beam is used in an existing solution. The semi-static adjustment means that a beam set is indicated using higher layer signaling (for example, Radio Resource Control (RRC) signaling), and beam set adjustment takes a relatively long time. As a result, the semi-static adjustment cannot eliminate the signal fading problem caused by blocking. Beams in a beam set are fixed within a period of time, and even if one or more beams in the beam set are blocked, the beam set is still used for signal transmission. When detecting data, a terminal needs to detect most or all signals on each beam before obtaining correct information through channel decoding. If the one or more beams are blocked, signals carried on the one or more beams cannot be detected, the terminal loses most information, and the correct information cannot be restored even through the channel decoding. In particular, in a scenario of transmission by levels in medium and high modulation code rate schemes (MCS), the existing solution cannot overcome the signal fading problem caused by blocking.